Gastro esophageal reflux disease (GERD) is a condition in which some of the stomach contents (solid and/or liquid) move backwards from the stomach into the esophagus (the tube from the mouth to the stomach). This action can irritate the esophagus, causing heartburn and other symptoms.
Gastroesophageal reflux disease (GERD), gastro-oesophageal reflux disease (GORD), gastric reflux disease, or acid reflux disease is defined as chronic symptoms or mucosal damage produced by the abnormal reflux of stomach acid to the esophagus. A typical symptom is heartburn.
This is commonly due to transient or permanent changes in the barrier between the esophagus and the stomach. This can be due to incompetence of the lower esophageal sphincter, transient lower esophageal sphincter relaxation, impaired expulsion of gastric reflux from the esophagus, or a hiatal hernia.
A different type of acid reflux which produces respiratory and laryngeal manifestations is laryngopharyngeal reflux (LPR), also called extraesophageal reflux disease (EERD). Unlike GERD, LPR is unlikely to produce heartburn, and is thus sometimes called silent reflux.
The gastrointestinal contents may thus also enter the respiratory tract as a result of any condition that causes the backward movement of the gastrointestinal contents from the stomach to esophagus. The gastrointestinal contents contain many substances that are likely to be harmful to the respiratory tract: acid, digestive enzymes, microorganisms, allergens, proinflammatory substances and so on. There is increasing evidence that gastro esophageal reflux disease (GERD) is the underlying mechanism behind many disease conditions of the respiratory tract, such as infections and high morbidity in subjects with lung transplants, asthma, bronchitis, bronchiectasis, pulmonary fibrosis and so on. At present, there are no acceptable methods to detect the entry of gastrointestinal (GI) contents into the respiratory tract.